Conventionally, as one type of hard magnetic disk devices, a magnetic hard disk drive which conforms to the Personal Computer Memory Card International Association (PCMCIA) “Type II standards” is known. This hard magnetic disk device comprises a mechanism part where a movable part exists and an electric circuit part for controlling this mechanism part. The mechanism part forms a shielded space and the electric circuit part is arranged outside this shielded space.
In the mechanism part, an actuator as the movable part is provided inside a frame body. This actuator causes a magnetic head for recording and reproducing information to shift with respect to a magnetic disk on and from which information is recorded and reproduced. The frame body is covered by a top cover. This top cover has an adhesive portion on the peripheral portion thereof, is adhered to the frame body by this adhesive portion, and shields the interior space thereof.
However, the following problems exist in such well-known devices.
Due to nonconformity in components and/or assembly, some devices need to be repaired after assembly before being placed on the market. However, the sealing structure of the device is constructed by, as mentioned above, adhering the top cover having the adhesive portion to the frame body, and when the top cover is opened for repairing the device, deformation occurs to the top cover, and the top cover cannot be reused. In this case, since the top cover is not low-priced, there is a problem such that the price of the device is raised.
The electric circuit part is assembled by means of a printed circuit board (hereinafter, referred to as a “PCB”). In the device, in order to cause an actuator to generate sufficient torque, a magnetic circuit for driving this actuator is thickly formed. In addition, the PCB is constructed while avoiding these thick components.
On the other hand, in recent years, a method (a ramp loading method) has been employed, wherein a magnetic head is evacuated to the outside of a magnetic disk during the non-operating time of a device. In the ramp loading method, since the magnetic head is evacuated to the outside of the magnetic disk, the rotation angle of the actuator increases. Then, inevitably, components forming the magnetic circuit become large.
Therefore, if the ramp loading method is employed in the well-known device, it is necessary to cut away the PCB greatly. As a result, the area for mounting electronic components decreases and a problem occurs such that these electronic components cannot be mounted or connection of an electric circuit becomes impossible. Meanwhile, if the mounting area of the PCB is secured, a problem occurs such that the ramp loading method cannot be employed or a voice coil motor becomes thin and it becomes impossible to cause the actuator to generate sufficient torque.